Polymer-based molded article with minimal flame spread and smoke properties

ABSTRACT

A molded article includes at least three layers: a cosmetic surface layer, an intermediate layer and a backing layer. The intermediate layer is an energy absorbing layer between the surface layer and the backing layer which at least partially confines burning to the surface layer, where flame spread is controlled, and smoke is minimized by the composition of the intermediate layer.

BACKGROUND OF THE INVENTION

The present invention relates to molded components and more particularly to polymer-based bath fixtures which minimize flame spread and smoke when subjected to combustion.

Tub surrounds are positioned within a recess built around a bathtub or shower. Conventional modular tub/shower units often include a tub portion at the bottom and two or more wall portions. The whole structure is inserted into the wall recess to form a waterproof surround. The fully enclosed waterproof structure is highly advantageous in that it prevents the escape of water into the wall cavity despite the shower spraying water onto the surrounding walls.

Tub and shower surrounds and other such polymer-based bath fixtures are typically molded through an open mold fiberglass reinforced plastic molding system. As the open molds transit the assembly line, spray stations perform particular spraying operation to produce the molded component. Such spray operations typically include an acrylic such as a gelcoat and resin/catalyst/chopped fiberglass fixture application. The chopped fiberglass provides a support structure for the component which supports the gelcoat aesthetic surface.

Although producing a high quality molded component, such polymer-based components may not meet certain requirements for flame spread and smoke according to particularly strict building codes. The polymeric materials are based on benzene ring chemistry, which may generate smoke and support combustion. Because additives that reduce flame spread tend to increase smoke generation and vice-versa, the use of chemical additives to polymer-based components to control these two parameters has had limited success.

Accordingly, it is desirable to provide a polymer-based component, which minimizes flame spread and smoke.

SUMMARY OF THE INVENTION

The molded article according to the present invention includes at least three layers: a cosmetic surface layer, an intermediate layer and a backing layer. Each layer is sprayed, in order, onto an open mold to build up the composite material molded article. The intermediate layer is an energy absorbing layer between the surface layer and the backing layer. The construction at least partially confines burning to the surface layer where flame spread is controlled and smoke is minimized by the composition of the intermediate layer.

The present invention therefore provides a polymer-based component, which minimizes flame spread and smoke.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:

FIG. 1 is a general perspective view of a molded article according to the present invention; and

FIG. 2 is a sectional view a portion of the molded article.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a general perspective view of a polymer based molded article 20. The molded article 20 is preferably a tub and shower surround, which is formed of multiple portions. Generally, a tub portion 22 receives wall portions 24 and 26 to form the molded article 20. It should be understood that any number of molded articles of any number of portions, such as shower bases, sinks, or other plastic faced components, will benefit from the present invention. Preferably, such components are relatively large bathroom-related fixtures.

Referring to FIG. 2, a sectional view through one of the portions 22, 24, 26 is illustrated. It should be understood that the sectional view may be taken anywhere within the portions 22, 24, 26. Each portion 22, 24, 26 preferably includes at least three layers: a cosmetic surface layer 28, an intermediate layer 30, and a backing layer 32.

Typically, each layer 28, 30, 32 is sprayed, in order, onto an open mold to build up the composite material component as generally understood, however, other manufacturing techniques will also benefit from the present invention.

The cosmetic surface layer 28 is preferably a layer of resin referred herein as “gelcoat”. The gelcoat is a hardenable polyester resin that becomes the visible surface of the finished product.

The backing layer 32 is preferably a sprayed layer of chopped fiberglass known as “chop.” Other chops such as a resin/catalyst/chopped fiberglass mixtures will also benefit from the present invention.

The intermediate layer 30 is an energy absorbing layer between the cosmetic surface layer 28 and the backing layer 32. The intermediate layer 30 absorbs energy in the form of heat from behind the exposed cosmetic surface layer 28 to delay ignition of the cosmetic surface layer 28. Furthermore, the composition of the intermediate layer 30 reduces the overall generation of smoke. The intermediate layer 30 is preferably an aliphatic resin with flame inhibitors such as aluminum trihydrate and other inorganic, non-flammable materials. The construction at least partially confines burning to the cosmetic surface layer 28, where flame spread is controlled, and smoke is minimized by the composition of the intermediate layer 30. Involvement of the backing layer 32 is minimized as the fuel from the cosmetic surface layer 28, which commonly provides ignition of the backing layer 32, is segregated therefrom by the intermediate layer 30.

Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined, unless otherwise indicated and will still benefit from the present invention.

The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention. 

1. A molded article comprising: a cosmetic surface layer; a backing layer; and an energy absorbing intermediate layer between said cosmetic surface layer and said backing layer.
 2. The molded article as recited in claim 1, wherein said intermediate layer comprises an aliphatic resin.
 3. The molded article as recited in claim 2, wherein said intermediate layer comprises a flame inhibitor.
 4. The molded article as recited in claim 3, wherein said flame inhibitor comprises aluminum trihydrate.
 5. The molded article as recited in claim 1, wherein said cosmetic surface layer comprises an acrylic.
 6. The molded article as recited in claim 1, wherein said backing layer comprises a chopped fiberglass.
 7. A molded bathroom fixture comprising: a cosmetic surface layer; a backing layer; and an energy absorbing intermediate layer between said cosmetic surface layer and said backing layer.
 8. The molded bathroom fixture as recited in claim 7, wherein said intermediate layer comprises an aliphatic resin.
 9. The molded bathroom fixture as recited in claim 8, wherein said intermediate layer comprises a flame inhibitor.
 10. The molded bathroom fixture as recited in claim 9, wherein said flame inhibitor comprises aluminum trihydrate.
 11. The molded bathroom fixture as recited in claim 7, wherein said cosmetic surface layer, said backing layer, and said energy absorbing intermediate layer form a wall of a shower surround portion.
 12. The molded bathroom fixture as recited in claim 7, wherein said cosmetic surface layer, said backing layer, and said energy absorbing intermediate layer form a wall of a tub surround portion. 